Over on the Fediverse, I said something:

Thesis: DNS is not meaningfully a database, because it's explicitly designed and used today so that it gives different answers to different people. Is it implemented with databases? Sure. But treating it as a database is a mistake. It's a query oracle, and as a query oracle it's not trustworthy in the way that you would normally trust a database to be, for example, consistent between different people querying it.

It would be nice if we had a global, distributed, relatively easily queryable, consistent database system. It would make a lot of things pretty nice, especially if we could wrap some cryptography around it to make sure we were getting honest answers. However, the general DNS system is not such a database and can't be used as one, and as a result should not be pressed into service as one in protocols.

DNS is designed from the ground up to lie to you in unpredictable ways, and parts of the DNS system lie to you every day. We call these lies things like 'outdated cached data' or 'geolocation based DNS' (or 'split horizon DNS'), but they're lies, or at least inconsistent alternate versions of some truth. The same fundamental properties that allow these inconsistent alternate versions also allow for more deliberate and specific lies, and they also mean that no one can know with assurance what version of DNS anyone else is seeing.

(People who want to reduce the chance for active lies as much as possible must do a variety of relatively extreme things, like query DNS from multiple vantage points around the Internet and perhaps through multiple third party DNS servers. No, checking DNSSEC isn't enough, even when it's present (also), because that just changes who can be lying to you.)

Anything that uses the global DNS system should be designed to expect outdated, inconsistent, and varying answers to the questions it asks (and sometimes incorrect answers, for various reasons). Sometimes those answers will be lies (including the lie of 'that name doesn't exist'). If your design can't deal with all of this, you shouldn't be using DNS.